I905-] DISCUSSION. 201 



plants in those fields which were resistant to the disease, and 

 were able to produce a desirable type of plant which was re- 

 sistant, while the majority of the crop was wholly destroyed. 

 Now by the selection of these individual plants in a field we are 

 developing resistant strains of a type, or a seemingly resistant 

 strain, to the root diseases which attack the tobacco crop. 

 That is a matter that we have been working on a great deal. 



Along the line of corn, as I said before, our most extensive 

 improvements have been carried on in the West, and have 

 shown that substantial improvement could be made in the yield 

 by the selection of ears which produce a vigorous strain of 

 corn, and by the selection of seed containing a larger per- 

 centage in protein and other valuable qualities. Some corn 

 that is grown in the West contains too high a proportion of 

 starch in order to make it a well-balanced ration for feeding 

 purposes, and we found there was a great variation in the per 

 cent, of protein and in the per cent, of yield, and by the selec- 

 tion of ears, which were high, we have been able, in the course 

 of four or five years' selection, to produce a strain carrying a 

 percentage of protein nearly double that of the crop when we 

 started. In other words, we have been able to increase it 

 from a little over seven per cent, to a little over fifteen per 

 cent, in the varieties which were treated in this way. In the 

 same way by the selection of the seed ear a change in the pro- 

 portion of starch was also brought about. 



The development of nitrogenous bacteria, which are more 

 active in the securing of nitrogen from the air and putting it 

 into condition where it is usable by the farm crop, has been 

 an interesting feature of the work in plant breeding during 

 the last two years. It was found that by crossing the bac- 

 teria, or the organism which forms the nodules on the roots 

 of clover and other leguminous plants, and putting them into 

 a condition where they could not secure any nitrogen from the 

 air that it was possible to produce strains of these organisms 

 or bacteria which were more active in the development or in 



